This invention relates to cooling of electronic components.
Higher heat densities in electronic equipment caused by the increasing density of integrated circuits and circuit pack configurations, has led to concern regarding the ability of unvented outdoor electronic cabinets to dissipate the heat generated by the electronics. The equipment is usually housed in shelves within an appropriate cabinet and cooled by fans. Fans can be adapted to blow recirculated coolant onto the components through a series of ducts (see, e.g., U.S. Pat. No. 3,387,648 issued to Ward, Jr., et al). Alternatively, a fan can draw air from outside the cabinet through openings in a wall of the cabinet and direct it over the components (see, e.g., U.S. Pat. No. 4,027,206 issued to Lee). Appropriate ducts can also be used to guide the air (see, e.g., U.S. Pat. No. 4,860,163 issued to Sarath).
Such cooling techniques, while generally adequate, are not necessarily effective in cases where a large number of high density circuit packs must be housed within a fairly small space, as in the case of subscriber loop carrier (SLC.RTM.) remote terminal channel banks. Such banks typically include channel units and common units which are each capable of generating up to 10 watts of heat. These circuit packs are mounted vertically with, typically, 28 circuit packs per shelf and 5 shelves per bank. Usually, banks are housed back-to-back in a cabinet with a small space between them.
The present method generally employed to cool unvented cabinets, which is to blow air into the banks, has reached the limit of its effectiveness. Attempts to increase cooling have generally involved use of heat pipes or finned heat exchangers without addressing the optimization of airflow within the cabinet.
It is, therefore, the objective of the invention to provide a means for enhanced cooling of electronic components mounted within an unvented cabinet by increasing internal airflow over cabinet surfaces exposed to outside air and increasing the flow of cooled internal air through the electronic equipment.